Die for cutting electrical units



6 Sheets-Sheet 1 A. W. FRAN KLIN DIE FOR CUTTING ELECTRICAL UNITS Dec.26, 1950 Filed May 11, 1946 NEY$ INVENTOR A bar'fW Franklin QAOQL ATTO-d ll Dec.26, 1950 A. w. FRANKLIN DIE FOR CUTTING ELECTRICAL UNITS 6Sheets-Sheet 2 Filed May 11, 1946 INVENTOR Alberf' W. Frank/1P BY ATTONEY.5

Dec. 26, 1950 A. w. FRANKLIN DIE FOR CUTTING ELECTRICAL UNITS 6Sheets-Sheet 3 Filed May 11, 1946 INVENTOR Alberf 'F anK/Ih BY 13 @44ATTORNEY5 Dec. 26, 1950 A. w. FRANKLIN DIE FOR CUTTING ELECTRICAL UNITSFiled Ma 11, 1946 6 Sheets-Sheet 4 Dec. 26, 1950 A. w. FRANKLIN2,535,674

DIE FOR CUTTING ELECTRICAL UNITS Filed May 11, 1946 6 Sheets-Sheet 5TiEIlEI.

INVENTOR Alberf Franklin NEY$4 Dec. 26, 1950 A. w. FRANKLIN 2,535,674

DIE FOR CUTTING ELECTRICAL UNITS Filed May 11, 1946 -6 Sheets-Sheet 6 Flc1. fa.

WZZW/i 2/ INVENTOR. AlberrW FmnKHn Afflqs.

Patented Dec. 26, 1950 UNITED STATES PATENT OFFICE DIE FOR CUTTINGELECTRICAL UNITS Albert W. Franklin, New York, N. Y.

Application May 11, 1946, Serial No. 669,197

8 Claims. I. s

This invention relates to improvements in electrical units of the typecomprising an insulating support having conductors attached to one facethereof.

A general object of this invention is to provide an improved form ofelectrical unit comprising an insulating support having conductorsattached thereon in the form of an inductance, as for example a radioloop antenna, an electrostatic shield, circuit conductors, and the like.

A more specific object of the invention is to provide an improved formof loop antenna unit consisting of an insulating support and acontinuous conductor attached thereto to provide an inductance having anall air dielectric and a high Q factor.

Another object of this invention is to provide a novel method ofconstructing electrical units of this type wherein a sheet of conductingfoil such as copper is simultaneously sheared and attached to aninsulating support.

A more specific modification of the preceding object is to provide amethod wherein an inductance is formed by means of a single continuousshear line.

Another object of the invention is to provide a method of simultaneouslyforming an inductance and attaching it to an insulating support byshearing a sheet of foil into a continuous strip and clinching the stripto the support and/or cementing it there.

A more specific object of the invention is to provide an inductance ofthis type with terminal connections simultaneously with the formationthereof.

Another specific object of the invention is to provide a method ofsimultaneously forming an inductance from a sheet of metal foil andproviding it with integral connecting tabs.

A still more specific object of the inven ion is to provide anelectrical inductance comprising at least two sets of windings, that isa primary and a secondary winding, simultaneously formed from a singlesheet of metal foil.

Another object of this invention is to provide a novel form of die bymeans of which inductances as hereinbefore described can be formed froma sheet of metal foil.

A still further object of the invention is the provision of a novel formof die of this type made up of a plurality of parts which may be readilyassembled and disassembled, and can be assembled in several ways toprovide a continuous formation of either clockwise or counter-clockwiserotation.

A still more specific object of the invention with respect to the die isto provide a die of this type made up of a plurality of parts which canbe disassembled to facilitate sharpening.

Another object of this invention is to provide a novel form ofelectrostatic shield constructed and manufactured in accordance with theprinciples of this invention.

Other and more detailed objects of the invention will become apparentfrom the following description of the embodiments thereof herein disclosed and illustrated in the attached drawings. This invention residessubsbtantially in the combination, construction, arrangement, relativelocation of parts, steps and series of steps, as will be fully explainedbelow.

In the accompanying drawings,

Figure 1 is a plan view with some portions broken away and othersomitted of an inductance specifically a loop antenna embodying thefeatures of this invention;

Figure 2 is a plan view of the die by means of which the loop antenna ofFigure 1 may be made;

Figure 3 is a transverse, central, cross-sectional view through the dieof Figure 2;

Figure 4 is an enlarged detailed plan view of a portion of the dieshowing the structural features by means of which the primary terminaltabs and one of the secondary terminal tab; is formed;

-Figure 5 is a plan view disassembled and Figure 6 is a plan viewassembled of the portion of the die by means of which one of theintermediate secondary terminals or the final secondary terminal isformed;

Figure 7 is a cro-s-sectional view through a portion of the die, theinsulating support and the metal ioil mounted thereon, showing therelation of the e parts ju t prior to the cutting operation the die;

Figure 8 is a similar view showing the relationship of the parts at theend of the cutting, forming and attaching operation of the die;

Figure 9 is a cross-sectional view through one of the tab formingportions of the die taken on the line 9-9 of Figure 4, showing therelationship of the parts at the same operating stag as illustrated inFigure 7 Figure 10 corresponds to Figure 8 and shows the relationship ofthese parts at the end of the cutting, forming and attaching operationof the die;

Figure 11 is a cross-sectional view taken on the line I l-l l of Figure4;

Figure 12 is a cross-sectional view taken on the line l2--l 2 of Figure4;

Figure 13 is a perspective view of several of the conductors and a pairof terminal tabs;

Figure 14 is a similar perspective view showing one of the intermediatetabs;

Figure 15 is a diagrammatic view illustrating something of the actionwhich occurs during cutting, forming and attaching of the conductors tothe insulating support;

Figureslfi and 17 are simple, diagrammatic views illustratinghow'themulti-part die can be assembled to form windings of reverse rotation;

Figure 18 is a plan view of an electrostatic shield constructed inaccordance with the principles of this invention; and

Figure 19 is an enlarged cross-sectionalview of a portion of thestructure of Figure 18 taken on the line iii-l9 of Figure 18.

Briefly, the object of this invention is taprovide novel and improvedforms of electrial units such as inductances, electrostatic shields,circuit to jithe'insulating support. The adhesive-may be apyae e'sivesuitable for the purpose and generally may Joe either of thethermosetting or ther b la ic type It ma b ia e he or :b oth of theadjoining faces'of the insulating sapport and the metal foil in anlysuitable manner, or may be interposedtherebetween in the form of athinsh'eet of material as-a separate element. fA thermoplastic form ofadhesive is preferred, and the die, by means of which the metal foil'iscut, is preferably heated to such a emperature that simultaneouslywiththe cuttingand forming bi'the sheet the adhesive is tened, aidinginattaching the resulting channel' sliaped' conductors to th insulatingsupport. In some forms'o'f the device, it is not necessary toiise 'anadhesive, since theclamping and clinchflifigactioh resulting'from theformation ofthe cut strips "into channel cross-section results in asufiioiently' strong connection between the two.

One highly useful form of structure, employing the'features of thisinvention, is illustrated in"-Figure 1, in the "form of a two-windinginductancesuitabl'e for use as a loop antennain radio receiving sets.The insulating support I'D may be 'of'a'ny suitable configuration, butfor use with'radio receiving sets may be of'such size and configurationas to form the back for the receivingset cabinet. This support can beofany suitable material, as for example fiberboard," of whichMaso'nitefis an examplaand various so-called plastic materials of whichBakelite is an example.

The convolutions of the inductanecon'sist of metal conductorsot'channel-shap'ed ionna'tion, for example V-s'haped cross section, as"is clear fromsuch figures as 8 and13. As illustrated, the inductancecomprises a single turn-primary 12 having the terminal tabs !3 and l tto which "terminal "connections can be made; by means-"of terminalloopsybinding posts; soldered connections, and the like. The secondaryl5 consists-of a plurality-of convolutions related convolutions llcomposed of a single channel-shaped conductor,"whi'ch for conveniencecan'be' sai dtdbegin at the terminal tab l6 and terminate'at theterminal tab 11. To insure clarity, it may be noted *generally ofrectangular form in that the conductors for any adjacent pair of sidesof a convol'ution m'e'et 'at aright angle as indicated at 90 in Figure 1. its will be clear as the description proceeds, 'the conductor iscontinuous, but is so formed marten-11m ar of rectangular form cabinet,for

fiet' andniountin the antenna'therein.

n A description of thedie by means of whih' tl ie structi 'e'iorinedno-w'folldws. 22"to w hich the parts indicatefclby'the re c'eiimneiarzs, consists of four parts, 25, 26, 2-1- and 29fwhichfareattached in assembled rjelation to the pla-te 22by means ofscrewsi28.Tl'ie-cutting porti'o'n"ofthe die-parts arses ve t-lie inde'rfas isclear from 4 t ing a outer 'fiang'e a-nd"=a*wider inner flange -3 whch-flanges scretvreceiving apertnres' a ie providd. The raised portions:d with a series ofst'ra'ight tini providiiigcontinuous 3|. Theen'ds of'the' d'i'e parts a re ut 511 e545 degree angle sothat these parts 'a'nbe assembled 'in rectangular relation, as clearly shown in Figure 2.

vr'y important iatiir e o f coiistruction of these die' panes that eachpair of opposite-sections areoi diifi'entlength'with respect to eachother. Thus the section 2 is shorter' than 'tlie *29*s shorterthan'thesemen 2 6. The difference inlen th' or tlieses'ec- 't'ionsis equaltoth'e pitch of the' coriv'olutions defining the cutting edg e 3 l-.clutti'ng edge Ton-the primary [2- is'conliiiiuousand the cutting edgefor the secondary I5 is continuousfibutvbetween thesetwo duttmg edeesthere-is an interh structural feature, namelythe di-fief 0c inlength-between the corresponding parts of each pair that it is possible"to cut a 'singlesheet ofliietal f'ciiL- as wiill b'e' s'till furtliefeiiplained belowfin onenperation into'a single continuous conductor-inthe *form'--of ea plurality ofconvolutions, or"in the case illustrate'd'into two such conductors. 'I'he'ditferehce {in length of th'e'pa'rts of'each'pairis equal to'th'e pitch of the convolutions, as previously 1mentioned.

This principle is rather-c earlyillustrated'in Figures 16 and1'7,as"well'* as*th'e principle of the formation of 'convolutions"ofeither "direction of rotation. The-cutting edgeC is'diagrarnmaticallyillustrated in these figures for' convolutionsmf rather large-pitch,wherirr the effect-Tofforming the die oi parts offidi'iierenti lengthbeconies apparent. 'As illustrated in Figures P16 and .17; the die is"composed of .the 'par'ts =A-,' B,'-C=and+D. -'I-'he partC'isiof alength greater thanthe corresponding 'part A byan-am'oun't equal tothepitch' of'the convolutions and the same is true ofthe part B 76 withrelation to the part D. With these parts assembled as shown in Figure16, a formation of clockwise rotation results- By reversing the parts,as shown in Figure 17, the same parts can be employed to cut a formationof counterclockwise rotation,

As clearly illustrated in Figure 2, the cutting edges meet at rightangles, resulting in the formation of rectangular convolutions, aspreviously explained.

, Portions of the die parts are cut away to permit the addition ofinserts by means of which integral tabs may be simultaneously cut andformed, at the time of the cutting and formation of the conductor. Thus,in Figures 1, 4, 5 and 6, it will be seen that the die parts are cutaway to provide several inserts of proper configuration. These insertsare illustrated at 32, 33, 3 3, 35, 31 and 38 and are attached to thebaseplate 22 by means of screws such as the screws 35 (see Figure 4).The insert 32 is provided with a triangular ridge forming the U-shapedcutting edge 39, and the ends of the insert are tapered, as are thecorresponding portions of the main die part 26, so that these parts meeton the diagonals 4:") and ll. This brings the cutting edge 39 into rightangle relation with the cutting edges 3| and together they form acontinuous cutting edge. The insert 33 is of quite similar form andjoins the main die along the diagonal faces 53 and 4d. The main die iscut out at 4| and 44, as indicated at 4! with regard to the insert 34,which meets the main die part on the diagonals 45 and 4? as before. Uponcomparison, it will be seen that the inserts 32 and 34 are quite similarbut are reversed in form. The spaces between these dies are filled byplain inserts 50 and 5| to provide a structure which appears as shown atthis region in Figure 2. The insert 3! is similar in construction andarrangement to either of the inserts 32 and 34. The inserts 35 and 38are illustrated in Figures 5 and 6. The main die is cut away so that theinsert can meet on the diagonals 49, bringing the cutting edge 48 andthe insert into right angle relation,

and in effect making the cutting edge 43 a continuation of the cuttingedges 3|. At this point it may be noted that the reference numeral I80represents the base of the V-shaped channel to aid in distinguishing thecutting edges 3|. Each of the inserts is provided with a punch 203operating in apertures 20: in the inserts. These punches serve toprovide small apertures in the tabs into which binding posts or clipsmay be riveted or otherwise attached. It may also be noted in passingthat Figure 12 may be helpful in understanding the construction of thedie at the point of mounting of one of the inserts.

The die unit comprising the base 22 and the die proper 23 (see Figure 2)is mounted in a press or other suitable machine for effectingreciprocation. When adhesives requiring heat are employed, the die canbe heated in any suitable and well known manner. An insulating supportIf) is placed on the bed of the die and a metal foil of the proper shapeor the end from a roll of metal foil is superposed thereon, as indicatedin Figure 7. As previously mentioned, if an adhesive is used, it willlie between the support It! and the foil 2|, and may be applied directlyto either or both by a coating or by the insertion of a thin separateunit of adhesive, as for example, a thin sheet of thermoplasticadhesive. The parts are then below the die, as is clear from Figure '7,and when the die comes down the cutting edges 3| shear the metal foil 2|along lines corresponding to the cutting edges 3|, and as the die isdriven home these metal strips are deformed into sharply peaked V-shapedchannels comprising th conductors I5, as illustrated in Figure 8.

Referring to Figure 15, it will be seen that as the triangular shapedcutting members are forced into the material of the support |0 underpres sure, the material will tend to flow upwardly, as indicated by thearrows, and be compressed and condensed behind the conductors l5, and asa matter of fact, forced a short distance above the plane of the top ofthe support In. The metal conductor strips and the material andsupporting base are brought into intimate contact under considerablepressure which tends to bind them together and when an adhesive is usedthe heated die softens it insuring still greater adhe sion therebetween.At this point it may be noted, adhesives which do not require heat maybe employed within the purview of this invention. The entry of thetriangular shaped cutters into the material of the base between thestrips forms, as will be clear, an air space between them so that thefinal product consists of an inductance or conductors which areseparated by an air space.

An important structural feature is illustrated in Figure 15 ascomprising the relative location of parts wherein the conductors |5 havetheir apices in a plane which is above the initial plane of thesupporting base it, while their lower edges are below that plane. Thisresults in the advantage that it is not possible to easily get an objectunder the edges of the conductors and thus force them loose. Thiscontributes to a structure which will stand normal handling without fearof breaking the conductors loose from the supporting base.

Figures 9 and 10 illustrate rather clearly how the tabs are likewisesheared out of the sheet and attached to the base. In practice the foilsheet 2| in outer dimensions will be slightly larger than the inductanceto be formed so that there will be a slight amount of foil wasterepresenting the original configuration of the sheet which is strippedoff from the base. This waste is not adhesively bound to the supportingbase even in the case where an adhesive is used. Likewise the centerportion of the sheet which remains undisturbed is stripped out to formthe final structure shown in Figure 1. If binding posts are rivetedthrough the apertures formed by the punches 200 the attachment of thetabs to the supporting base is further insured.

Upon consideration it will be seen that the planar width of theconductor which is formed into channel shape is equal to the pitch ofthe convolutions forming the article. This is one way of stating thatthere is no waste material formed between the convolutions, eliminatingany stripping operation and resulting in the desirable requirement thatthe conductors have a maximum conducting cross-section available.Simultaneously the air space between turns re sults in providing anallair dielectric inductance between the adjacent surfaces of theconductors.

From the above description it will be seen how a spiral of rectangularformation results and why the adjacent sides of each convolution meet atright angles.

The advantage of this die construction will also be well understood whenit is realized that by removing the die parts 25, 25, 21 and 29 from theplate I2, they may be readily sharpened by a suitably shaped abrasivewheel. The abrasive wheel'can enter the V-shaped grooves and travelcontinuously fromend to end. Allcutting edges are straight so that thedie parts can easily be sharpened in available grinding machines.

electrostatic shield constructedin accordance'with the subject matter ofthis invention isillustrated in Figures 18 and'l9. In this casethe-supporting base similar to the base 19, is illustrated at I I0.Asheet of metal foil is placed thereon and a die, which is much simplerin this case, is employed tocut, form and attach the conductorscomprising the shield. "The shield consists of a transverse conductor Hifrom which radiate laterally a series f parallel conductors I [2 oftriangular cross-section. A portion of the die for this construction -isillustrated at I 5 4. The triangular shaped rods l l5 provide thestraight cutting edges by 'means of whichthe conductors H2 are formed."However, in this case each conductor is formed bya pair or" cuttingedges which are spaced a distance representin the spacing between thefinished :conductors- H2. These cutting edges form triangular grooves inthe supporting base- I I9, as illustrated at H3. 'As before, the partsare preferably arranged so that the lower edges of the-conductors H2 arebelow the plane'of the base l It while their apices are above .theplane. Adjacent pairs of cutting edges-are joined to cut the metal andgroove the base, as indicated at I it", at-the ends where the conductorsi [2 are attached to the transverse conductor H I.

-'-A single transverse cutting-edge is provided on the-die toshear thesheet-and groove-the base along the line H3. Thus'an electrostaticshield attached to asupportingbase, all as illustrated in Figure -13,-is formed from a single sheet of foil. There will be a strip along thelefthan'd edge comprising waste, as; Well as a grid nomprising thestrips between the-conductors H2 and-the conducting :strip along therighthand edge which will likewise be removed as waste. When athermosetting adhesive is employed as previously mentioned, the die [14will be heated but the areas between the cutting edges 'w-illnbesufiiciently relieved so that they donot contact the'metal foil in theareas between theconductors-thus facilitating :strippingof the wastefrom between the conductors.

-'It now followsfrom the-previous-description how other electricalconducting configurations can be constructed in accordance with theprinciples of this invention, as for example circuit wiringconfigurations. By-employng meansiof this invention, it will be seenthata series of parallel conductors can be formed-with a minimumofspacing attainable when cutting them "-from' asingle sheet of metal.'By constructing the "dieof the proper formation :various circuitcombinations can be simultaneously formed from asingle sheet of metaland-attached toa supporting base. "-It' is contemplated that within theprinciples of this invention the circuit. wiring for electricalapparatus can thus-be simply and inexpensively' formed.

In all forms of structure made inaccordance awith'this invention, :it ispreferable to shape :the

die; so as .to formN +shapedconductors having an -;acute: angle.'Especiallywhen these conductors are used for the transmission of highfrequency ialternating currents: they will ,be found entirely suitablein'viewof the well known fact that such .icurrents travel onthegsurface-of the conductor.

"A hollowvv-shaped-iconductor makes itpossible :ztouget: theamaximumnumber-.of parallel -.co.n i1

tors in a given space while obtaining the maxihim surface area. anddielectric insulatinglspace between .them. "The electrostatic heldbetween the conductors .is mainly through the .air and only .a .small.-portion of the electrostatic field will pass through the dielectricmateriaLof :the supporting base, thus reducing the dielectric losses toa minimum.

Another advantage of this form of conductor in thecombination disclosedis the mechanical advantage-of the clinching and gripping action which asharply angled V -shaped conductor-provides. The sharply angledconductor, as previously explained, gripsthe raised material of theinsulatingbase, aiding -in -the mechanical attachmentof the conductor tothe base. In theelectrpstat shi of the type .si sc qse w iehis nqrma lplace clos t t 1mm nt na. t r hered iqrm v 12cm. luste al w .masimr'i eaci er o ine .ra i en ls .ws t th ouehwh e ex ing. e me e to th externa.Iie 9 e lo p .tner hr e i ne. duysnrrent ss i th shie d- Itshouldalsofbe noted that the turns comprising, the primary andsecondary of atwocoil .induct nc may -be.r n0re widel p ce than i lustrated-in thisfigure. .If the turns of the primaryare to be spaced in the turns of,the secondary, the die will be so formedthat metal canbe hip b w n inrrm s T iQ P 1 1 ima nd h :Qu mm t r i 4 v the secondf Y an s r s ac njhfil b t a wan a com ish mdi ingh L a vthi r gion. i a cord nq wl thfirfin i l i l t din Fi u is. so. theta s i efmeiale th .d s re wiclt i bforme which en-h strippe -ou 4 "Thisapplic tion is an n in at imp r ofmy eop d eepplicat on S ia N 7, 5 fi1ed i y-1 28,1;19A5, now-Patent-ZAS11725, issued October 19.31948.

:From the above description itwill .be apparent .to those. skilled.intheart that the subject'matter 0511131 118 invention .islcapable ofconsiderable variae tion, andI do not, therefore; desire to. be. limitedto the illustrated embodiments herein set forth. Iprefer. to be'limi-ted only as required by theappended claims.

-:What is-claimed is:

'1. A metal cutting-die comprising a base-platehaving'a-multi-part-diemember secured on one race -thereof, said diemember parts'meeting on diagonal lines in pairs-and having grooved'faces to form spaced cutting edges, the cutting edges of saidparts'being related to form a continuous cutting edge-from end to end.

' -yAd as s rib wm r s n a weanin platea rectangular die secured tooneiqw of said plate, m r sine rrt meeti Q .diase ia lines to form arectangular configuration, each-oi .ne heme e hepeder .i r inaac ean e Ith .-.1.eemb aat 9 1 a ai aad rabl inserts mounted on said plate andhaving cutting edges meeting the cutting edges of the main die at rightangles.

'7. A die of the type described comprising a supporting plate andcutting members mounted on said plate comprising four parts meeting ondiagonal lines to form a rectangle, each of said parts having straightequally spaced channels formed on the face thereof to provide a seriesof parallel cutting edges, one part of each opposite pair being shorterthan the other part by an amount equal to the distance between saidcutting edges whereby the parts are assembled to form a continuouscutting edge from end to end.

8. In the combination of claim 7, one or more of said parts havinginserts with cutting edges 15 dovetailed therewith so that the cuttingedges of the inserts form continuations of said cutting edge of the die.

ALBERT W. FRANKLIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 838,423 Kitsee Dec. 11, 19061,582,683 Harmon Apr. 27, 1926 2,165,394 Lyness July 11, 1939 2,277,826Giroux Mar. 31, 1942 2,388,838 Egli Nov. 13, 1945 2,401,472 FranklinJune 4, 1946 2,451,725 Franklin Oct. 19, 1949 FOREIGN PATENTS NumberCountry Date 13,045 Great Britain June 10, 1898 596,830 Germany May 11,1934

